Register an extra hobby for Stuart. The hobbies are stored in an array inside the 'value' object. The $watch() method is triggered because the 'deep' option is set to 'true' so that the watcher also detects changes further inside the object.
Register an extra hobby for Stuart:
Current 'value' object:
{ "owner": "Stuart", "address": "Faraway Lane", "hobbies": [ "Bird watching", "Trail running" ] }